With the tropical storm nearby, NASA opted to take Atlantis back to its vehicle assembly building.

Mission managers' slim hopes that the shuttle could launch today were dashed by Monday's early-morning forecast that Ernesto would regain hurricane strength and rumble by Kennedy Space Center.

"We did get a change in the forecast from the National Hurricane Center this morning that had us even more concerned about Ernesto," said shuttle weather officer Kathy Winters.

It's unclear when NASA will try again.

Winters said that projection had Ernesto passing 15 nautical miles west of the space center Wednesday

Sitting out there on Launch Pad 39B: a fully-fueled shuttle Atlantis with a 35,000-pound, 45-foot long payload of solar arrays bound for the international space station.

Launch integration manager LeRoy Cain said he released the ground team responsible for helping the astronauts execute their mission: "We told folks they should go back to their home centers until we can pick a new launch date."

After Atlantis' commander, U.S. Navy Capt. Brent Jett, and his crew leave quarantine they may head back to Houston to conduct another simulation of their 11-day mission.

The shuttle was cleared for liftoff after lightning struck the launch pad Friday, but ensuring there was no damage closed Sunday and Monday's launch windows.

The first step in rolling back the shuttle is to drain its fuel cells. Next, disable the explosives used to separate the shuttle from its external fuel tank and solid fuel rocket boosters after launch.

Then the shuttle is loaded onto a massive crawler. The four-mile ride to the 52-story vehicle assembly building takes six hours.

Shuttle launch manager Mike Leinbach said NASA wants to start the rollback at 8 a.m. today because rough weather is projected to hit the space center in the afternoon. The shuttle cannot be moved in sustained winds of 46 mph or greater.

This would be the fifth time a storm forced a shuttle rollback: Tropical Storm Klaus in 1990, Hurricane Erin in 1995 and Hurricanes Bertha and Fran in 1996.

Once the shuttle is back inside the VAB, it will take eight days to prepare it for launch. NASA officials would not commit to a new launch window Monday, but did say they are looking to October and December.

A September launch grows more doubtful with each day because of a scheduling conflict with the Russian Space Agency. A Soyuz spacecraft is set to dock with the station in mid-September.

Still, NASA holds out a slim hope that weather conditions will change enough to allow Atlantis to remain on the launch pad today for liftoff this weekend.

The last shot is this morning, before the orbiter is lifted off the launch ramps and onto the Shuttle Crawler Transporter.

"In my mind that is unlikely," Leinbach said. "But we always hold out hope for that."